Floating roof tank and piping therefor



Oct. 5, 1-948. I w. ca. LAlRD 2,450,758

I FLOATING ROOF TANK AND PIPING THEREFOR Filed June l5, l944 JQVENTOR- WILBUR G. LAIRD ATTORNEY an even number and preferably of equal length, and also includes a control mechanism adapted to cause the upper end of the swing line to move vertically in a straight line as the pipe line folds or unfolds. This control mechanism comprises a series of interconnected rigid links, which in the example shown, includes a short rigid link 28 fastened at one end by a pivot joint to the midpoint of the pipe 28 and at the other end to one end of a long link 38, the midpoint of which is secured by a pivot connection .to the middle of the pipe section I 8. The lower end of the link 30 is provided with a wheel or roller 32 which is permitted to move only in a straight-line horizontal path by a long retaining bracket 34 fixed to the bottom I 2 of the tank.

In the example as shown, the length of the rigid link 38 which may be made of any suitable material is the same as that of the pipe sections l8 and 28, while the link 28 is one half the length of the link 38. These relationships are understood to be based upon the lengths between pivot points of the pipe sections and links, the axis of roller 32 being a pivot point. It will be apparent from a consideration of the relationships created by the pipe and link arrangement as shown that when the swing line either folds or unfolds, the upper open end (at the point of cableattachrnent) must follow a straight-line vertical path; This action not only avoids a thrust on the floating roof, but actually tends to prevent effective thrust from other causes, and also tends to keep the roof from rotating.

While the link 38 and the pipe sections l8 and 20 are illustrated and described as being of the same length from pivot to pivot (link 28 being one half), and provide a very practical and compactarrangement (which also provides for vertical movement of the sheave 18 of Fig. 3), it is not necessary that all links and pipe sections have these relationships. So long as the links and pipe sections together form a parallelogram they will yield the desired result. Vertical movement is also obtained if in the four-sided figure formed by the link and pipe sections, the link portions are equal and the pipe portions are equal, even though the length of the link portions is different from that of the pipe portions in the figure. pipe sections may be compensated for, by providing a suitably formed retaining bracket and track for the roller 32, where its path is not horizontal, so that vertical movement at the desired point is obtained. These modifications and relationships apply to all forms of the invention.

Since the floating roof of the tank shown in Fig. 1 is open to the atmosphere, it is necessary to provide a drain line. In this instance the drain line is constructed, and functions in exactly the same manner as the swing line described above, except that it is fixed to and connected through the edge of the crowned roof plate I'd. As shown, the drainage line for the roof comprises a plurality of rigid pipe sections 36' and 38 connected by fluid tight swivel joints to an outlet line 40 and to a fixed pipe connection 42,

, the same relationships as the: links 28 and 30,

although the other relationships referred to may Other length relationships of links and.

4 be used. The drainage line with its connecting links 44 and 46 folds and unfolds in the same manner as the swing line, and causes the pipe connection 42, and the portion of the floating roof connected thereto, to move in a straight path vertically as the liquid level in the tank changes.

In the floating roof tank as shown in Fig. l, the swing line mechanism and the drainage line mechanism are mounted at the points to each other and near the edge of the roof so that together they not only do not cause thrust action on the floating roof, but actually tend to stabilize the floating roof and prevent rotation. If desired, drainage lines of the type shown may be placed on opposite sides of the floating roof or at any other point or points, depending upon the drainage characteristics of the particular roof to be drained.

The tank shown in Fig. 2 is a similar to that shown in Fig. 1 and comprises a shell 48 and a bottom plate 50. In this instance, the floating roof comprises a roof plate 52 surrounded by an apron 54 secured to the plate in fluid-tight manner and which extends above and below the plate. The downward extending portion of the apron 54 is adapted to seal in the liquid and to trap gas below the roof plate 52, which may be removed through a dome 56. The gas collected under the plate 52 may be removed from the dome 56 by means of a gas line comprising a plurality of rigid pipe sections 58 and 68 of equal length and which are connected together, and to an outlet connection from the dome 5G by means of swivel joints. The pipe section 68 is also connected by a swivel joint with a pipe line at the top of the tank which is fixed thereto by means of a bracket 62.

The operation of the gas discharge line including the sections 58 andfill is controlled by means of a rigid link mechanism such as that described above in connection with Fig. 1. The links comprise an upper short link 64 and a long link 66, the lower end of which is provided with a wheel or roller adapted to move back and forth in a horizontal bracket frame 68. The bracket 68 and the interconnected links 64 and 66,- together with the pipe sections 58 and 60 restrict the folding and unfolding action of the gas line so that the point of connection to the dome 56 must move in a straight-line vertical path.

The gas line mechanism shown in Fig. 2 is preferably mounted close to the edge of the floating roof, and the roof is preferably provided with a drainage apparatus identical with that shown in Fig. 1. The gas line comprising pipe sections 58 and 68 may if desired be used for supplying liquid to the tank or for supplying gas thereto. The gas may be supplied from any source and for any desired purpose as for example from a gasoline tank having a fixed roof. In fact, the floating roof shown in Fig. 2 may be provided with a relatively long downwardly extending apron which seals in the liquid in the tank, so as to provide for a relatively large maximum gas capacity above the liquid level in the tank.

Fig. 3 shows a modified form of the swing line mechanism shown in Fig. l in which means is provided for operating the swing line from the outside of the tank instead of from the floating roof. This means is illustrated as comprising an outside winch Ill, and a cable 12 which passes over a sheave 14 mounted on the rim of the tank wall. The cable 12 also passes through a liquid sealing tube 1-6 in a dome near the edge of the floating roof, then around a sheave 1'8 mounted at the pita-of the links-it an'dtll, from ante-{a {e te'ndslto 2. lug BI] undergthedome. v j

" From the 'rel'ationshipoi; the pipe sections 118 Z0, and the links '28 and. in 3 "(which are the same as in Fig. 1), itwill'be "apparent th'atas the floating 'roofmoves up and down in the "tank, theupper end of the-pipe section will remain in exactly thes'ame relative position; In

form of the apparatus, the swing line not rigidly fixed tothe floatingroof but-the vertical straight line motion tends to keep the fioating "root from rotating and from shifting in the tank. 1 The weight "of the swing line mechanism is "su ported by the cable 12 around the sheave 1-8 and will also "tend to prevent anythrust 'ac'tion'jor rotation of the floating .roo'f. The ortion of the c able T2 outsidethe tank or the winch mechanism 'may be "employed to indicate the position -ofthe swing line in relation tothe roof.

Figs. 4 and -5'illustra'te a method o fattacliin 1 upper end of a swingline to a floating "deck whereby the open end of the swing line maybe "ad'j'ustedfverticai ly in relati-ontothe floating :roof

while thrust is eliminated and the floating roof is prevented irom rotating. The apparatus;

shown'in Figs.- 4 and 5 Comprises a swing line composed of a plurality (preferably. an even number) of rigid"pip'esections"82 and 84 connected :to'getherlnnd to ailine leading :irom the tank through wall 81. the bottom of, thetank-Billoy means .of a clamp as shown. 'in'Fi'gl Ithe'sW'ingline in Figs. 4 and 5- includes a link mechanism 90 which is mounted and Y which operates-in exactly the "same manner as that-sho-w-n in Fig. 'ti'f'lthe pipe 82 .is provided with a pair of flanged :side wheels 92 which .are movable up and down between vertical members 9 1 comprising 'a part oi a frame work erected under "a :dome 96 in the floating roof 98. may be moved up and down with respect to the floating roof by means of a threaded shaft member I00 which passes through a corresponding threaded member attached to the axle of one of the wheels 92. The threaded member I00 is provided with a hand wheel above the dome 96.

By operating the hand wheel on the member I00, an operator may set the outlet of the swing line shown in Figs. 4 and 5 at any desired point either below or above the liquid level in the tank. With this mechanism furthermore, the swing line apparatus, including the link means 90, prevents lateral movement of the dome' 96 as the floating roof moves up and down in the tank with.

changes in the tank contents. The mechanism therefore has the function of preventing any thrust action by the swing line, and at the same time prevents rotation of the roof (the swing line preferably being mounted near the side of the tank).

It is to be understood that in zig-zag folding piping in which more than two pipe sections are employed (an even number being preferred), each section will be pivoted at an intermediate point to a link member. For example a four section line would have three long links and a short one. The pivot or swivel joints are preferably adapted to permit only up and down motion of pipe sections and links, although other motion may be provided for if desired.

The swing lines shown in Figs. 1, 3, 4 and 5 may be used for the removal orsupply of gas to or from under a floating roof of the type shown in Fig. 2, as Well as for the removal and supply of liquid. Under normal conditions, the swing Line 86 may fastenedito.

The upper end The upper end of the pipe 82- iinesshown in rigs-61,53, 4, and-=5 will in heldiip heabove the'iiquid level. I I "Inerect-inga drainage line such as that comprisingthepipe' sections 36" and 3 8, the links 44 and 46', together with the "roller attached to the link {4% maiy -bereversed, so that the =rolleroperates insufbsta-n-tially;- horizontal position under the floating' roof instead of operating along the bottom o'f'the tank; I

From theforegoing description of the various forms of theinvention; it will be apparent that theapplicant provided advantageous zig-za'g memepiping arrangements for liquid storage tanksw-hich are particularly adapted for use v i It will 'be tur- *the'rri-iore apparent *'that various modifications maybemade'such as the'use of one or more of the lines {For supplying lire extinguishing fluidsmr tor other purposes. such modifications are contemplated within the spirit and scope of the present invention, asshown by the appended claims; Haa/ing-describedthe invention in its preferred fern-1; what-is claimed as new is: g 'flj ln a liquid storage apparatus including a said line comprising an even number 'of rigid pipe se'ctionsof substantially equal length interconn-ected ;by swivel joints-' and connected to a fixed "outlet pipe mm -s'a id tarrk by a 'swivel joint, la. plurality-of interconnected rigid l'in'ks =pi-votally connected endto end and *t'othe niidponitsof each pipe section,- a' terminal link of said plurality of links pivoted at' its mid-point to the pipe -section connected to' the oujtlet p ipe a-nd *having a tree end held in horizontal straight line sliding engagementw lth a per-tron =of'said tank 'near said fixed 'ou'tlet pipe, lt'heother terminal link'being about one half the len-gth of a pipe section and having one end pivoted to a pipe section, said links being connected with each other and with said pipe sections in a parallelogram arranged so as to control the folding and unfolding action of said sections.

2. A liquid storage apparatus comprisin a tank and a floating roof therein, two swivel-jointed zigzag pipe lines each vertically mounted in said tank at right angles to each other and'eacah having one end opening thereinto, and attached to the roof, each of said lines comprising an even number of rigid pipe sections interconnected by swivel joints and connected to a fixed pipe line leading from the tank by a swivel joint, and means connected with each of the pipe sections of each pipe line and adapted to control the folding and unfolding action of said lines so that the open end of each pipe line is caused to move in a substantially vertical straight line said means for each line including a rigid link for each pipe section, the links being connected end to end lwitlh pivot joints, one terminal link being one half the length of the other links and having an end pivoted to one terminal pipe section at its midpoint while the remaining links are respectively pivoted at their mid-points to the mid-point of corresponding pipe sections, the free end of the other terminal link being mounted in restricted horizontal sliding engagement with the container.

3. A drainage apparatus for a movable roof for a container, comprising a down drain line having its upper end connected to the roof by a swivel joint and its lower end connected to a fixed outlet underthe floating ro'of, so that their outlets will line at the bottom of the container by a swivel length of the other linksand having an end pivoted to one terminal pipe section at its mid-point While the remaining links are respectively pivoted at their mid-points to the mid-points of corresponding pipe sections, the free end of the other terminal link being mounted in restricted horizontal sliding engagement with the container.

4. In a liquid storage apparatus comprising a tank member and a floating roof member therein, a swivel jointed foldable pipe line mounted in said tank having one end opening thereinto and attached to said roof member, said line comprising an even number of rigid pipe sections of approximately equal length interconnected by swivel joints and connected to the tank member by a swivel joint, and means including a series of rigid links connected end to end by pivot joints, a link of said series being connected with each of said pipe sections at substantially their midpoints, and a terminal link of said series having an end mounted in sliding straight line engagement with one of said members, said links being connected with each other and with said pipe sections in such a manner as to form a. parallelogram involving the swivel joint between adjacent pipe sections, thereby to restrict the folding and unfolding action of said line to cause substantially vertical movement of the open end of the line.

5. A liquid storage apparatus comprising a tank and a floating roof therein, a vertically foldable swivel-jointed zig-zag pipe line in the tank having an end opening into the tank and attached to the floating roof, said pipe line comprising an even number of rigid pipe sections of equal length interconnected by swivel joints and connected to armed pipe line leading from the tank by a swivel joint, a rigid link for each pipe section, the links being connected end to end by pivot joints, one terminallink being one half the length of the remaining links and having its projecting end pivoted to the mid-point of one terminal pipe section, the remaining links being of the length of the pipe sections and pivoted at their mid-points respectively to the remaining pipe sections at their rnidpoints, the projecting end of the other terminal link \being mounted for restricted horizontal movement by a track member.

. 6. Apparatus as defined by claim 5 in which a holding means is provided for retaining the open end of said line in a substantially fixed position with respect to a point on said floating roof and in which said holding means includes a pivoted connection.

WILBUR G. LAIRD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,445,091 Kueffer Feb. 13, 1923 1,636,963 Jagschitz July 26, 1927 1,761,700 Bailey June 3, 1930 1,857,362 Day May 10, 1932 1,897,779 Wiggins Feb, 14, 1933 r 1,928,905 Meyers Oct. ,3, 1933 

